This invention relates to a valve structure for controlling fluid flow between respective inlet and outlet ports, the structure being of the type comprising a housing defining a cylindrical valve chamber, at least two axially spaced ports communicating with the chamber, and a valve rod and valve disk within the chamber, the disk being movable axially between alternative positions respectively establishing and blocking communication between the ports.
A three-way valve of the above type is disclosed, for example, in applicant's prior U.S. Pat. No. 4,078,579. In the prior arrangement, the valve includes a pair of axially spaced ports on one side of the chamber, and a third centrally located port on the other side of the chamber. The valve disk is movable between positions on opposite sides of the third port, so as to connect the third port with one (or other) of the axially spaced ports, while blocking communication between the third port and the other (or one) of the axially spaced ports. The valve disk is of a flexible nature and flips overcenter in moving between its respective positions.
Three-way valves of the type referred to in the quoted patent have diverse uses, and are particularly suitable, for example, in the liquid flow circuits of recreational vehicles and the like where, when winterization of the circuit is required, connection is to be made to a source of anti-freeze solution, not otherwise used in the circuit. The valves operate generally satisfactorily in this and other applications. However, when flexible valve disks are used, pressure forces acting on a disk resulting from fluid flow through the valve, may tend to distort the periphery of the disk out of sealing engagement with the circumferential wall of the valve chamber, resulting in valve leakage.
The present invention provides a means for effectively reducing the aforesaid leakage.